Residents of a Temple Hills neighborhood are on a heightened alert after a 15-year-old girl was sexually assaulted by gunpoint in front of her 26-year-old sister before the sister knocked the unknown suspect on the ground and caused him to run away Thursday night.

Prince George’s County police are now investigating the incident and seeking the suspect while residents are creating an awareness campaign to deter the suspect from returning.

Around 11:10 p.m., the two sisters were walking near Easy Street and Kingston Drive in the Westchester Estates neighborhood when they were approached from behind by a man wearing a mask. Police say the man pointed a handgun at both sisters and forced them into a wooded area. The suspect proceeded to sexually assault the younger sister, but the 26-year-old defended her sister by tackling the suspect to the ground, said Cpl. Clinton Copeland, a county police spokesman.

Copeland would not disclose the nature of the sexual assault based on the sensitivity of the case and those involved.

The suspect then struck the older sister several times using the blunt end of his handgun and ran away, said Copeland. Both sisters were treated for injuries and later released from an area hospital.

Police are asking anyone with information to contact the county police department’s District 5 investigative section at 301-868-8773 or Crime Solvers at 866-411-TIPS.

Copeland said detectives on the case say the sisters were outside after 11 p.m. because it was a pleasant evening and they were enjoying the weather.

A concerned resident in the neighborhood, who wished to remain anonymous out of fear that his family may be targeted by the alleged attacker, said he lives close to where the assault occurred and plan to stay indoors until the suspect is apprehended.

He said he and some of his neighbors are creating fliers that include a description and composite sketch of the suspect and plan to post them throughout the neighborhood and hand them out to area businesses. He said he believes the suspect may be a resident of the area given that he was on foot when the assault occurred late at night.

“Needless to say, I was pretty upset when I saw [reports of the incident] because of the close proximity to my home and it especially scared me because I have four children,” he said. “I have been on walks with my family from 6 to 9 p.m. during nice weather and have had incidents of young men driving slowly past us, circling around the block more than once, basically, chasing us back home because I would just have a feeling that something was wrong.”